基于板—梁理论的钢管混凝土翼缘工字形梁组合扭转与弯扭屈曲理论研究

发布时间：2018-08-11 14:54

【摘要】：对于现代社会而言,建筑结构逐步向着大跨度、大高度的方向发展,钢管混凝土组合结构是目前使用范围较为广泛且具有良好发展前景的结构构件。钢管混凝土翼缘工字形梁是一种新型的组合构件形式,其截面具有较高抗弯刚度以及抗扭刚度,可提高构件强度和平面外稳定性,此外钢管混凝土翼缘的存在一定程度上降低了腹板的高度,腹板的高厚比较小,对抗剪也是有利的。钢管混凝土翼缘工字形梁由钢材和混凝土两种不同材料组成,在组成形式上又可以看作是开口-闭口-实体部件的组合,这使得其相关的理论研究变得更为复杂,且不能套用现有的理论公式。目前关于钢管混凝土翼缘工字形梁组合扭转和弯扭屈曲的理论研究更是极少见到,而解决其扭转问题更是解决弯扭屈曲问题的必要前提。本文依据张文福教授提出的板—梁理论思想,从钢管混凝土构件自由扭转问题入手,对双轴、单轴对称钢管混凝土翼缘工字形梁组合扭转与弯扭屈曲问题进行理论研究,并利用有限元方法验证理论推导的正确性。本文的主要研究内容有:(1)基于板—梁理论,对钢管混凝土梁自由扭转问题进行理论分析,给出方形、矩形钢管混凝土梁自由扭转时的总势能及自由扭转刚度的表达式,利用ANSYS软件建立方形、矩形钢管混凝土悬臂梁有限元模型各12根,提取自由端扭转角与理论进行对比,验证理论推导及自由扭转刚度的正确性。(2)基于板—梁理论,对钢管混凝土翼缘工字形梁组合扭转问题进行理论分析,给出双轴、单轴对称钢管混凝土翼缘工字形梁组合扭转时的总势能、自由扭转刚度、约束扭转刚度表达式,建立能量变分模型和微分方程模型,并给出扭转角的解析解,利用ANSYS软件建立双轴、单轴对称钢管混凝土翼缘工字形悬臂梁有限元模型各12根,提取自由端扭转角与理论对比,验证理论推导及自由扭转刚度、约束扭转刚度的正确性。(3)基于板—梁理论,对钢管混凝土翼缘工字形梁弯扭屈曲问题进行理论分析,给出双轴、单轴对称钢管混凝土翼缘工字形梁弯扭屈曲时的总应变能、总初应力势能、总势能的表达式,并给出单轴对称钢管混凝土上翼缘工字形梁截面不对称系数的计算方法,同时建立其能量变分模型和微分方程模型。(4)基于钢管混凝土翼缘工字形梁弯扭屈曲总势能表达式,给出简支梁在纯弯、均布荷载、跨中集中荷载作用下的弹性弯扭屈曲临界弯矩计算公式,利用ANSYS软件建立双轴、单轴对称钢管混凝土翼缘工字形梁有限元模型各12根进行特征值屈曲分析,验证临界弯矩公式的正确性。
[Abstract]:For the modern society, the building structure is gradually developing towards the direction of long span and large height. Concrete filled steel tube composite structure is widely used and has a good prospect of development. Concrete-filled steel tube (CFST) flange I-shaped beam is a new type of composite member. Its section has higher bending stiffness and torsional stiffness, which can improve the strength and out-of-plane stability of the member. In addition, the existence of CFST flange reduces the height of web to a certain extent, and the thickness of web is small, so it is advantageous to resist shear. Concrete-filled steel tube (CFST) flange I-shaped beams are composed of two different materials, steel and concrete, which can be regarded as the combination of open, closed and solid components, which makes the related theoretical research more complicated. And the existing theoretical formula can not be applied. At present, the theoretical study on composite torsion and bending and torsional buckling of concrete-filled steel tube flange I-shaped beams is rarely seen, and solving the torsional problem is the necessary prerequisite to solve the bending and torsional buckling problem. Based on the theory of slab-beam put forward by Professor Zhang Wenfu, and starting with the problem of free torsion of concrete filled steel tube (CFST) members, this paper makes a theoretical study on the combined torsion and bending and torsional buckling of concrete filled steel tubular (CFST) flange I-shaped beams with biaxial and uniaxial symmetry. The finite element method is used to verify the correctness of the theoretical derivation. The main contents of this paper are as follows: (1) based on the slab-beam theory, the free torsion problem of concrete-filled steel tubular beams is theoretically analyzed, and the expressions of the total potential energy and the free torsional stiffness of square and rectangular concrete-filled steel tubular beams are given. The finite element model of square and rectangular concrete-filled steel tube cantilever beams is established by using ANSYS software. The torsion angle of free end is extracted and compared with the theory to verify the correctness of theoretical derivation and free torsional stiffness. (2) based on slab-beam theory, The combined torsion problem of concrete-filled steel tubular (CFST) flange I-shaped beams is theoretically analyzed. The expressions of total potential energy, free torsional stiffness and restrained torsional stiffness of uniaxial and uniaxial symmetric I-shaped beams with concrete filled steel tube flange are given. The energy variational model and differential equation model are established, and the analytical solution of torsion angle is given. The finite element models of biaxial and uniaxial symmetrical steel tube concrete flange I-shaped cantilever beams are established by using ANSYS software. The torsion angle of free end is extracted and compared with the theory. The theoretical derivation and the correctness of free torsional stiffness and restrained torsional stiffness are verified. (3) based on the slab-beam theory, the bending and torsional buckling of concrete-filled steel tubular flange I-shaped beams is theoretically analyzed, and the biaxial analysis is given. The expressions of total strain energy, total initial stress potential energy and total potential energy during bending and torsional buckling of uniaxial symmetrical steel tube concrete filled steel tube flange I-shaped beams are given. At the same time, the energy variational model and differential equation model are established. (4) based on the total potential energy expression of bending and torsional buckling of concrete-filled steel tube flange I-shaped beams, the load distribution of simply supported beams in pure bending and uniform distribution is given. The calculation formula of critical bending moment of elastic bending and torsional buckling under concentrated load in span is established by using ANSYS software. The finite element model of biaxial and uniaxial symmetric steel tube concrete flange I-shaped beams is established to analyze the eigenvalue buckling of 12 I-shaped beams. The correctness of the critical moment formula is verified.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9

【参考文献】